Electromechanical interlock



July 28, 1931. 1-. BRADY ELECTROMECHANICAL INTERLOCK 3 Sheets-Sheet 1Filed Feb. 18, 1927 4% M INVENTOR ATTORNEY July 28, 1931. T. BRADYELECTROMECHANICAL INTERLOCK Filed Feb. 18, 1927 3 Sheets-Sheet 2 1 AMINVENTOR AT'I'ORNEY BY "'u July 28, 1931. T. BRADY ELECTRQHECHANICALINTERLOCK Filed Feb. 18, 1927 3 Sheets-Sheet 3 VI Q m 6 mm m w M m. m La V T 5 a m M M 6 a. m F fl AM. mm? M H mu m m w M @W mm m I. v.\ m I wH w into the bracket 8 and are arranged to draw the two sides of theslot 12 toward each other, thereby securing the link 11 to the bracket8. At its other end, the operating link 11 extends through a slotprovided in a bracket 14. Screws 15 secure the link 11 to the bracket14. The bracket 14 is pivotally connected to a second operating link 16by means 0t a screw 17. Operating'link 16 extends into a slot providedin a yoke member 20 and is secured to this yoke member by screws '21.Yoke member 20 is pivotally mounted on a pin 22 that is carried bybracket 23 Bracket 23 is secured by screws to a'wall plate 24 which inturn is likewise secured to wall of the hatchway.

Although various arrangements of closing means may be employed forclosing the door,'a suitable form of door closing and checking device,indicated as'a whole by the the numeral '28. has been illustrated forthis purpose. The door closing and checking device isconnected tooperating link 1.6. The details'of the door closing and checking deviceand the manner in which the deviceis connected to link 16 are clearlyshown in'Figure 4. The yoke member 20 is formed with a downwardlyextending bifurcated lug'25. A tongue formed ona nut member 26 extendswithin the bifurcation of the lug and is pivotally connected to this lugby a pin 27 extending through aligned apertures provided in the lug 25and in the tongue of nutimember 26. Nut

member 26 is threadedon the piston rod of the door closing and checkingdevice 28 and is retained on this piston rod by a lock nut 29. 7 I

The piston rod 30 has a check piston 31 secured to its bottom end foroperation within the check cylinder 36. Piston 31 is formed with anaperture 32 extending therethrough from the top to the bottom 1 and atthebottom of this piston the aperture is enlarged to form a valve seatfor a ball 33,. Theball 33 is retained in the enlarged portion oftheaperture by a pin 34. The check piston 31 is rabbeted at .35. The

' lower portion of cylinder 36 is adapted to receive fluid, such as oil,and a filling open- 111g 37 1s provided in this cylinder at the desiredliquid level. A threaded'plug 38 is used to close the filling opening37.The

inner surface of the check cylinder 36 is provided with longitudinalgrooves that extend from the filling opening 37 to the upper limitottravel'of the check piston 31. A cap 41'is threaded into the upper endof the check cylinder and serves as a bearing for the pistoirrod 30. Aplug 42 is threaded into the lower end of the check cylinder. A gasket43 is used to seal the connection between the plug 42 and the I checkcylinder. Plug'42 has a downwardly a by-pass 44 extending from a pointjustabove the plug 42 to a point above the filling opening 37. A needlevalve 45 is used to adjust the efliective area of the bypass The checkcylinder 36 (Figures 1 and 4) has two seniiannular flanges 46 and 47extending upwardly therefrom. These flanges are arranged to grip acylindrical casing 48, thereby securing this casing to the checkcylinder 36. Casing 48 is composed of two semicylindrical portions and51. Bolts 49 extend through apertures provided in opposed lugs formed onthe flanges 46 and 47 and when the device 28 is assembled these boltsare turned so as to draw flanges 46 and 47 toward each other, therebybinding the two portions 50 and 51 together. The

upper end of the cylindrical casing 48 is closed by an end cover 52 thatis divided along a diameter and the two halves thus formed are heldtogether and in gripping engagement with the casing 48 by bolts 53. Endcover 52 is provided with a circular aperture through which a sleeve 54extends. The upper portion. of sleeve 54 is adjustably threaded upon thepiston rod 30 and is secured in position'on this rod by a lock nut 55.Nuts 56 are threaded upon the. lower end'ot sleeve 54. A spring clamp 57rests upon a washer carried by the nuts 56 and grips the upper end of atension spring 58. The lower end of the tension spring 58 is secured. tothe check cylinder 36 by eye-bolts 60 that extend through aperturesprovided in the check cylinder.

An interlocking bar 64 of rectangular cross-sectiomhas its lower endpivoted upon the pin 27 that connects the yoke member 20 to the pistonrod of the door closing and checking device 28. This interlocking bar isalso illustrated in Figures 6 and 7 From the pin 27 the interlocking bar64 extends upwardly through an aperture 65 of rectangular cross-sectionprovided in a guide bracket 66. A locking pin'67 has its ends fixed inthe guide bracket66 and its central portion spans the aperture 65. Thelocking The releasing lever 74 comprises a body portion 75 and threeshoulder portions 6, 77 and 78 that extend outwardly from the bodyportion. When the dooris in its closed position with locking pin 67 inrecess 70, the shoulder portion 76 rests against the interlocking bar 64and forces this bar against the locking pin.

An interlocking switch 87 of any desired form is connected to thereleasing lever 74 to be operated'thereby. The details of theinterlocking switch chosen for illustration and the manner in which theswitch is connected to the releasing lever 7 4 is shown in Figures 1, 3and 5. The outer end of the shoulder portion 7 6 of releasing lever 74is bifurcated and an angle member 80 is pivotally connected to thisbifurcated end by means of a pin 81. The top of the angle member 80 is'apertured and the lower end of a rod 82' extends through this apertureand issecured to the angle member by nuts 83.- The upper end ofthe rod82 extends through an aperture provided in the head of a headed pin 84.Nuts are also used to secure this end of the rod 82 to'the pin 84. Pin84 is carried by the bifurcated end of the operating lever 85 for switch87. Lever 85 is pivotally mounted on a pin 86 that is carried by lugsformed on the casing of switch 87. The switch casing is secured byscrews to the wall plate 24. A link 88 has one end pivotally connectedto the operating lever 85 and its other end pivotally con nected to aswitch bar 90. Switch bar 90 is made of insulating material and has anU-shaped contact plate 91 secured to its lower end. Contact plate 91 isarranged to bridge stationary contacts 92 and 93. Contacts 92 and 93 areincluded in a control circuit for the elevator motor. While contactplate 91 is in engagement with contacts 92 and 93 the elevator motor maybe operated to movethe elevator car along the hatchway.

The body portion 75 of releasing lever 74 is provided with an aperture94 that is of rectangular cross-section (see Figures 6 and 7 A bar 95has its lower end extending into the aperture 94. A pin 89 extendsthrough aligned apertures provided in the body portion 7 5 and in thelower end of bar 95 and pivotally connects the bar 95 to the releasinglever 74. The upper end of bar 95 is bent at right angles to thecenterline of this bar and is apertured to accommodate a rod 96. Rod 96extends through the aperture in the upper end of bar 95 and has acompression spring 97 surrounding its lower portion. Spring 97 bears atone end against the upper end of bar 95 and at its other end against aspring seat 98 supported on rod 96 by nuts threaded on the lower end ofthis rod. The upper end of rod 96 has a yoke member 100 threadedthereon.

Yoke member 100 is pivotally connected to a bifurcated end of a lever101 by a pin 102. Lever 101 is fulcrumed between its ends on a pin 103extending from a bracket 104. The other end of lever 101 is alsobifurcated and is pivotally connected by a pin 106 to the lower end of alink 105. When the door is locked in its closed position the lever 101bears against a buifer 99 that is carried by an angle member 109. Anglemember 109 is secured to the bracket 104. The upper end of link 105 ispivotally connected by a pin 107 to the bifurcated end of one arm of abell crank lever 108. The bell crank lever 108 is fulcrumed on a pin 110extending from the bracket 104. The other arm of the bell crank leverhas a forked end that carries a pin 111 upon which is rotatably mounteda roller 112. The bracket 104 is secured by screws to the wall of thehatchway.

The elevator car 117 (see Figure 3) carries a retiring cam designated asa whole by character 113. This cam comprises a cam rail 114 connected bylinks 115 and 116 to the car 117. Links 115 and 116 are pivotallyconnected to the cam rail by pins 118 and 120 and are also pivotallyconnectedto the car by pins 121 and 122. The upper end of the cam rail114 is connected by a yoke 123 to a chain 124. Chain 124 passes overidler sheave 125' and is connected to the shaft 126 of a retiring cammotor 127. An abutment 128 is secured to the cam rail 114 and isarranged to coact with the upper surface of a buffer 130 to determinethe extended position of the cam rail. Buffer 130 is carried by abracket 131 that is secured to the car. An abutment 132 is also securedto the cam rail 114 and is arranged to coact with the lower surface ofbufi'er 130 to determine the retired position of the cam rail.

The operation of the locking device is as follows:

Assume that an intending passenger is at the floor illustrated in'Figure1 and that the car 117 is not in use and is positioned in the hatchwayat some other floor, the hatchway door for which is closed. It is to benoted that the intending passenger is unable to open the door 1 as it islocked by the locking pin 67 acting through the interlocking bar 64 andyoke member 20 to prevent movement of operating links 16 and 11.

Upon pressing the hall button (not shown) the intending passenger causesthe energization of the retiring cam motor 127 Motor 127 operates-towind chain 124 upon shaft 126, thereby raising the cam rail 114. As thecam rail 114 is raised the links 115 and 116 cause this member to moveinwardly toward the sideof the car until the abutment 132 strikes thebuffer 130, thereby effecting the disengagement of the retiring cam fromthe roller 112 of the operating mechanism member. and rod 82 to the forthe door at the floor where the: car is positioned. This results in thelocking of this door, as will be explained later in connection with thestarting of the car from the floor shown in Figure, 1; V

The car then moves to the intending passengers floor and comes to rest.Although the time that the retiring cam motor is deenergized woulddepend upon the arrangement of the control circuits, it will be assumedthat this motor is deenergized as the car comes to .rest at the floor.The cam rail 114 then fallsunder the action of gravity unwinding thechain 124 from shaft 126 until the abutment 128 carried by rail 114strikes the buffer 130, whereupon the retiring cam comes to rest. Thelinks: 115 and 116 cause the cam rail 114 to move outwardly as itdescends, thereby effecting the engagement of this cam rail with roller112. The engagement of cam rail 114 with roller 112 causes bell cranklever 108 to turn about the'pivotal pin 110 in a counterclockwisedirection as viewed in Figure 1. This motion of hell crank 108 istransmitted through link 105, lever 101, rod 96, spring 97 and bar 95 tothe releasing lever 74 and causes the releasing lever to swing upwardlyabout its pivotal pin 73. k lever 74 starts to swing upwardly theshoulder portion 76 disengages the. interlocking bar 64. The upwardmovement of shoulder portion 76 is transmitted through angle operatinglever of switch 87 and causes this lever to turn about its pivotal pin86.- This movement of lever85 raises the switch bar to eitect thedisengagement of contacts 92 and 93, thus opening the elevator motorcontrol circuit in which these contacts are included. During thismovement of the releasing lever 74 and the operation of switch 87, theshoulder ortion 77 of the releasin lever strikes the interlocking bar 64and turns this bar about its pivotal pin 27 in a clockwise directionuntil the slot 70 of the bar 64 disengages the. locking pin 67. .Theparts are so arranged, however, that the slot 70 does not fullydisengage pin 67 until after switch bar 90 disengages contacts 92 and93. During the movement of the releasing lever, its shoulder portion 78moves from one side of the'interlocking bar to the other, passing overthe beveled end 71 of the bar.

opened by the intending passenger. The links 11 and 16, not being inhorizontal alignment when the door is closed, permits the'door, onceunlocked, to be moved to open position. During the opening movement theoperating links 11 and 16 swing upwardly about their pivots, causing theinterlocking bar 64 to move upwardly between the shoulder portions 77and 78 of releasing lever 74 on one side and shoulder portion As thereleasing 76 on the other side. The piston rod 30 and sleeve 54 of thedoor closing and checking device 28 move upwardly along with theinterlocking bar. The upward movement of piston rod 30 causes the checkpiston 31 to move upwardly in the check cylinder 36. This movement ofthecheck piston 31 is not resisted by the liquid in the check cylindersince ball 33 moves away from its valve seat during the upward movementof the check piston and permits liquid to pass from above the piston 31through the aperture 32 to the space below this piston. The upwardmovement of sleeve 54 causes the extension of tension spring 58. Thepositions assumed by the various parts of the locking device at the endof the opening movement are as illustrated in Figure 3.

The passenger may now enter the car and release the door. Upon the doorbeing released, the spring 58 of the door closing and checking devicecauses the sleeve 54 and piston rod 30 to move inwardly ofthe casing 48,thus effecting the downward swing-v ing of operating links 11 and 16 toclose the door. During this movement of these members the interlockingbar 64 moves downwardly until the recess 70 is opposite the locking pin67. There is no engagement between the recess 70 and the locking in 67because the shoulder portion 77 holds the interlocking bar 64 away fromthe pin 67. The check piston 31 moves with the piston rod 30 and towardthe end of the closing movement this check piston enters the portion ofthe check cylinder 36 that is not grooved. As the ball 33 rests againstits valve seat during this downward movement, a portion of the liquid inthe check cylinder is trapped under the piston 31 and is forced to passthrough the restricted by-pass 44. Thus the motion of the check pistonand of the connected apparatus, including the door 1, is checked towardthe end of the closing operation.

Upon pressing the car button (not shown) corresponding to the landing towhich the passenger desires to be taken, the retiring cam motor 127 isenergized. This motor operates to cause the chain 124 to wind upon theshaft 126, thereby raising the cam rail 114 as previously described. Asthe cam rail 114 is retired the weight of the releasing lever 74 and ofthe mechanism connect- The door 1 isnow unlocked and may be ing lever 74to the roller 112 causes the releasing lever to swing downwardly aboutits pivotal pin 73. As the releasing lever commences to swing downwardlythe shoulder portion 77 moves away from interlocking bar 64 and thisbar, owing to its own'weight, moves toward the locking pin 67 and causesthe recess 70 to engage the locking pin, thus locking the door 1. If forany reason the interlocking bar should fail to move into lockingengagement with the locking pin,

then further movement of the releasing lever causes shoulder portion 76to strike this bar and thereby force it into such looking engagement;During the latter part of its movement, the releasing lever causes theswitch bar '90 to move the contact plate 91 into engagement with thecontacts 92 and 93, thereby completing the elevator motor controlcircuit in which these contacts are included. These parts are soconstructed and arranged that the plate 91 cannot bridge contacts 92 and93 until after'the recess 70 engagespin 67 to lock the door. Theelevator motor thereafter causes the car to be moved toflthe desiredfloor. Should the retiring cam motor be energized while the car is at afloor with the door'1 open, this motor will retire the cam, permittingthe releasing lever to swing downwardly. The motion of the releasinglever is arrested, however, by the shoulder portion 78 engaging theinterlocking bar at one side and shoulder portion 76 engaging theinterlocking bar at the other side. When the releasing lever comes torest the contact plate ,91 will still be above the contacts 92 and 93and, asthe motor control circuit in which these contacts are included isnot completed, the elevator motor cannot start and the car remains atrest until the door is closed and locked. I

Undervcertain conditions of operation the roller 112 and bellcrank lever108may be swung by the retiring .cam to such an ex tent as to causeshoulder portion 78 of the releasing. lever to strike the wall plate 24.Any further movement. of the roller and bell crank lever will merelycause spring 97 to be compressed without injuring the door lockingdevice. 7

It is to be noted that when the door is locked the interlocking bar 64is held in firm engagement with the locking pin 67 by the weight of thereleasing lever combined with that of the mechanism connecting thislever to the bell crank lever 108.

The door operating mechanism shown in Figures 8 to 11 inclusive isillustrative of mechanism suitable for hatchway doors of elevatorsystems of the type wherein the elevator car is provided with anoperator. The operating links 165 and 166 for the door 167 are arrangedin a manner similar to that described for operating links 11 and 16above described. With the door in closed position, however, the links165 and 166 are horizontal and in alignment. Link 165 is provided with ahandle 133. The interlocking bar 129 .is pivotally connected to the yokemember 168 into which the link 166 extends and tothe piston rod for thedoor closure and checking device, as previously described forinterlocking bar 64. The interlocking bar cooperates with the lockingpin 139 ;to lock and unlock the door.

The releasing lever 135 instead of being actuated by a motor operatedretiring cam is arranged to be mechanically operated by the caroperator. In order to carryout this mechanical operation, a pedal 136 ispositioned in the car where it will be convenient for actuation by theoperators foot. Pedal 136 has a shank that extends through an apertureprovided in one arm of a bell crank lever 137. Lever 137 is pivoted on apin carried by a bracket 159. Nuts 138 are threaded on the shank oipedal 136 and abut this arm or" the lever 137. The other arm of lever137 is connected by an adjustable link 140 to one arm of a lever 141.other arm of lever 141 is connected by an adjustable link 142 to one endof a tension spring 143. The other end of spring 143 is connected to apin 144 extending from the underside of the car floor 145. Lever 141 issecured to a shaft 146 by set screws. Shaft 146 extends through bearings147 .and 148 formed on a casting 150. Casting 150 is attached by bolts151 to an angle member 152 that is secured to the underside of the carfloor 145. A lever 149 of a retiring cam is pinned on the shaft 146 andhas its outer end pivotally connected to the lower portion of a cam rail153. The upper portion of cam rail 153 is pivotally connected to a link154 that in turn is pivotally connected to a.

plate 155 formed on the casting 150. The cam rail 153 is arranged tocooperate with a boss 156 formed on a lever 157. A square shaft 158extends through an aperture of square cross-section provided in the hubof lever 157. Shaft 158 also extends through similar apertures formed intwolevers 160 and 161. Levers 157, 160 and 161 are retained on shaft158by set screws. Lever 161 is pivotally supported on a pin 162 carriedby a bracket 163 that is secured to the hatchway door sill. Lever 1 60is pivotally connected to a vertically extending link 164. Link 164 ispivotallyconnected to the releasing lever 135.. v

The tension spring 143 acts through lever 141 shatt 146 and lever 149 tohold the cam rail 153 in its retired position and away from the bossexcept when the cam rail is held in its extended position by the actionof the car 0 aerator. With the cam rail 153 in its retiree position thepedal 136 extends upwardly into the car.

hen the car is at a landing with the door closed and locked, should theoperator desire to open the door he pushes the pedal 136 downwardly intothe position illustrated in Figure 9. This movement of pedal 136 istransmitted by nuts 138 on the shank of this The iao

causes lever 157 together with levers 160 and 161 and shaft 158 to turnas a unit about thefpin 162. The movement 'of lever 160 causes link 164to move upwardly, thereby effecting the upward swingingof releasing 87and thereafter the disengagement of interlocking bar 129 and unlock thedoor.

The operator may now open the door by means of handle 133. Owing to thefact that links 165 are in horizontal alignment, the toggle jointbetweenthese links must be broken as a part of the door opening operation. Thistoggle joint is automatically broken by pulling on ,the handle 133. Thisarrangement, however, prevents the unwarranted opening of the door, asby intending passengers from the outside, even though interlocking bar129 and locking pin 139 locking pin 139 to are disengaged, for the'forceapplied by such person to open the through links 165 and 166 in astraight line to wall plate 134. Thus, as there is no force tending toswing the operating links upwardly about their pivots, the toggle jointis not broken and the door can not be opened.

The operator by releasing the handle 133 permits the door closing andchecking dedoor is transmitted 'vice to operate to close the door aspreviously described in connection with the arrangement illustrated inFigures 1 to 7 inclusive. Upon his releasing the pedal 136 the tension,spring 143 acts through the link 142 to swing lever 141 in a clockwisedirection as viewed in Figure 9. This movement of lever 141 istransmitted through shaft 146 and lever 149 to the cam rail 153 andcauses this rail to be retired; This movement of lever 141 is alsotransmitted through.

link 140 and bell crank lever 137 to the pedal 136 and causes the pedalto move upwardly to its normal position in the car. The retiring of thecam rail permits the releasing lever 135 to turn, under the action ofgravity, about its pivotal pin in a direction to eflect the locking ofthe door. Continued movement of the releasing lever after the door islocked causes the switch 87 to close, thereby permitting operation ofthe elevator; Should the pedal 136 be released while the door is stillopen, the releasing lever 135 will fall until its shoulder portionsengage the interlocking bar 129 in the 111311118X described inconnection with the arrangement, illustrated in Figures 1 to 7inclusive. Under such conditions the switch 87 cannot close and theelevator cannot be operated until after the door has been closed andlocked.

It is to be understood that a retiring cam cooperate with saidarrangement and operating motor, such as illustrated in Figure 3, may beemployed in conjunction with the operating linkage illustrated inFigures 8 to 11 inclusive instead of the pedal arrangement shown.

' Also, it is to be understood that the electromechanical interlock maybe applied to other forms of door operating mechanism, regardless ofwhether this mechanism is operated by the application or" manual orother power.

As many changes could be made in the above construction and manyapparently widely different embodiments of this invention could be madewithout departing from the scope thereof, it is intended that all mattercontained in the above description or shown in the accompanying drawingsshall be interpreted as illustrative and not in a limitingsense. I

What is claimed is:

1. In an elevator system, a-hatchway door, linkage connected to saiddoor for effecting the operation of the door, a stationary pin, a barconnected to said linkage and arranged to engage said pin, with the doorin closed position, to hold the linkage in fixed position thus lockingthe door. a

2. In an elevator system, a hatchway door, door closing means, linkageconnecting said door closing meansto the door, a bar connected to saidlinkage, a member arranged to cooperate with said'bar, and means foreffecting the movement of the bar into 00- operating position with saidmember to lock the door in its closed position and for effecting themovement of the bar out of cooperating position with'said member tounlock'the' door. I

3. In an elevator system, a hatchway door, linkage connected to saiddoor for effecting the operation thereof, a locking pin, aninterlo-cking bar pivotally connected" to said linkage and arranged tocooperate with said pin, and a releasing lever, said releasing leverbeing arranged to move said nterlocking bar into engagement withsaidlocking' pinto prevent the operation of said door.

, 4. In an elevator system, a hatchway door, door closing means, linkageconnecting said door closing means to the door, a stationary lockingpin, an interlocking barpivotally connected to said linkage and arrangedto pin, and a releasing lever adapted to cooperate with saidinterlocking bar, said releasing lever being arranged either to causesaid interlocking bar to move into engagement with the locking pin andthereby effect the locking of the door or to cause said interlocking barto move out of engagement with the locking pin and thereby effect theunlocking of the door.

5. In an elevator system, a hatchway door, door closing means,

locking pin, an interlocking bar pivotally connected to said linkagearranged to cooperate with said pin, a releasing lever adapted tocooperate with said interlocking bar, and means for operating saidreleasing lever, said releasing lever, during its operation causing theinterlocking bar to move out of cooperative position with the lockingpin thus effecting the unlocking of the door. 6. In an elevator system,a hatchway door, linkage connected to said door for effecting theoperation of the door, a stationary looking pin, an interlocking barpivotally connected to said linkage and arranged to cooperate with saidinterlocking bar, a releasing lever, and means for operating saidreleasing lever to cause this lever to move the interlocking bar into orout of cooperative engagement with the locking pin to efiect the lockingor unlocking of the door; 7. In an elevator system, a hatchway door,operating linkage for said door, an interlock switch having an operatingmember, a pivoted releasing lever connected to said member and having aprojection formed thereon, a stationary locking pin, an interlocking barpivotally connected to said operating linkage and disposed in the pathof the projection on said releasing lever, said bar having a recess forengaging said looking pin with the door closed to lock said linkageagainst operation, and means for moving said releasing lever about itspivot to cause the opening of said switch, said releasing leverprojection engaging said interlocking bar during the movement of thereleasing lever to cause the interlocking bar recess to disengage saidpin after the opening of said switch, thus unlocking said linkage topermit the opening of said door, said releasing lever, during its returnmovement with the door closed, causing the locking of said linkage andthereafter the closing of said switch.

8. In an elevator system, a hatchway door, operating linkage for saiddoor, an interlock switch having an operating lever, a releasing leverhaving projections thereon, and connected to said operating lever, astationary locking pin, an interlocking bar pivotally connected to saidoperating linkage and disposed in the path of the projections on saidreleasing lever, said bar being provided with a recess, one of saidprojections holding said interlocking bar so that the recess thereinengages said locking pin with the door closed to lock said linkageagainst operation, and means for moving said releasing lever about itsfulcrum to cause the switch operating lever to open said switch, anotherof said projections engaging said interlocking bar during the movementof the releasing lever to cause the interlocking bar recess to disengagesaid lockingv pin after the opening of said switch, thus unlocking saidlinkage to permit the opening of said door, said releasing lever, duringits return movement, causing the interlocking bar recess to engage saidlocking pin to lock said linkage, provided the door is closed,

lever having projections thereon, and connected to said operating lever,a stationary locking pin, an interlocking bar pivotally connected tosaid operating linkage and disposed in the path of the projections onsaic releasing lever, said bar being provided with a recess, one of saidprojections holding said interlocking bar so that the recess thereinengages said locking pin with the door closed to lock said linkageagainst operation, and means for moving said releasing lever about itsfulcrum to cause the switch operating lever to open said switch, anotherof said projections engaging said interlocking bar during the movementof the releasing lever to cause the interlocking bar recess to disengagesaid locking pin after the opening of said switch, thus unlocking saidlinkage to permit the opening of said door, said one and still anotherof said projections cngaging said interlocking bar during the returnmovement of the releasing lever to stop this lever, should the door beopen, and thereby prevent the closing of said switch.

10. An electromechanical interlock tor hatchway doors provided withoperating mechanism comprising, a switch, a stationary pin, a barpivotally connected to the door operating mechanism, said bar having arecess and being biased to cause said recess to engage said pin and lockthe door in its closed position, and a releasing lever associated withsaid bar and operatively connected to said switch, said releasing leverbeing movable to cause the operation of the switch and thereafter thedisengagement of the recess from the pin to unlock the door.

11. An electromechanical interlock for hatchway doors provided withoperating mechanism comprising, a switch, a stationary pin, a barpivotally connected to the door operating mechanism, said bar having arecess and being biased to cause said recess to engage said pin and lockthe door in its closed position, a pivoted releasing leverassociatedwith said bar and operatively connected to said switch, saidreleasing lever engaging said bar in one position to maintain saidrecess in engagement with said pin, and means for causing pivotalmovement of said releasing lever from said one position and also forcausing the return of said releasing lever to said one position, saidreleasing lever, during its movement from said one position, causing theopening of said switch and thereafter the disengagement of the recessfrom the pin to unlock the door to permit the opening thereof and,during its return to said one position with the door closed, permittingthe engagement of said recess and said pin to lock the door and causingthe closing of said switch, said lever engaging said bar during saidreturn movement in the event that said recess is not in engagement withsaid pin to insure the engagement of the recess and pin and the 100kingof the door prior to the closing of said switch.

In testimony whereof, I have signed my name to this specification.

THOMAS BRADY.

rsieovz

